Semiconductor devices are commonly found in modern electronic products. Semiconductor devices perform a wide range of functions such as signal processing, high-speed calculations, transmitting and receiving electromagnetic signals, controlling electronic devices, photo-electric, and creating visual images for television displays. Semiconductor devices are found in the fields of communications, power conversion, networks, computers, entertainment, and consumer products. Semiconductor devices are also found in military applications, aviation, automotive, industrial controllers, and office equipment.
Semiconductor devices are often susceptible to electromagnetic interference (EMI), radio frequency interference (RFI), harmonic distortion, or other inter-device interference, such as capacitive, inductive, or conductive coupling, also known as cross-talk, which can interfere with their operation. The high-speed switching of digital circuits also generates interference.
Conductive layers are commonly formed over semiconductor packages to shield electronic parts within the package from EMI and other interference. Shielding layers absorb EMI before the signals can hit semiconductor die and discrete components within the package. Some shielding layers are electrically coupled to ground through a package substrate to improve performance. Many challenges exist in forming a shielding layer using a simple process that also has good electrical connectivity to ground.